Lately electric vehicles and plug-in hybrid vehicles equipped with a storage battery and a motor are becoming popular. In an apartment house, a sales office or the like where many such vehicles are charged simultaneously, a main breaker of a switchboard may trip when power consumption totaled with other load apparatuses exceeds a specific value. On the other hand, it is not desirable to reinforce equipment in order to prevent tripping of the main breaker due to an overloaded circuit, or to increase power under contract with a power company as power consumption increases.
According to the control performed in a prior art disclosed in Japanese Patent Application Laid-Open No. 2009-136109 (hereafter “Document 1”), a charging state of a storage battery is detected when each vehicle is connected with an external power supply, and an estimated power consumption and time of starting use are detected for each of a plurality of vehicles, and the required charging electric energy is calculated based on the detected charging state and estimated power consumption, and a charging schedule on charging time and charging electric energy of each vehicle is determined based on the required charging electric energy and time of starting use, and the storage battery mounted on each vehicle is charged based on the charging schedule.
In other words, according to the prior art disclosed in Document 1, the charging schedule on the charging time and the charging electric energy of each vehicle is determined based on the required charging electric energy and time of starting use of each vehicle, and the storage battery equipped in each vehicle is charged based on the charging schedule, therefore tripping of the main breaker due to an overloaded current can be prevented without increasing the power under contract with a power company.
In order to charge a storage battery in a vehicle, a connector of a charging cable must be connected to a charging port installed in the vehicle. Therefore according to the prior art disclosed in Document 1, a connector connection detecting unit, to detect whether the connector is connected to the charging port, is installed in the charging control device. This type of connector connection detecting unit is constituted by a proximity sensor, a micro-switch or the like that is installed in the connector, and transmits the detection result on the connector connecting state via a signal line.
However in the case of detecting whether a vehicle is connected or not using a dedicated sensor, as in the prior art, not only the sensor but also the wiring of the signal line, to transmit the result detected by the sensor, is required, which increases cost. Instead of a connector connection detecting unit, an operation input accepting unit (e.g. a touch panel with a liquid crystal monitor) to accepted operation input on the garage entering time or leaving time of a vehicle, for example, may be installed in the charging control unit. If this operation input accepting unit is installed, the cost increases even more than the connector connection detecting unit.